Note: Descriptions are shown in the official language in which they were submitted.
1~4~
A conventional composition comprising a resin dispersed in
water which is utilized to form an organic coating on metal surfaces by
immersing the surfaces in the composition, will result in a coating
whose thickness is the same regardless of the time the composition is
contacted with the surface. In order to obtain a thicker coating, it
has been necessary to subject the metal surface to a multiple stage
coating operation or to employ a bath having higher solids content - ~`
therein. In addition, these conventional systems ordinarily do not form
organic coatings on the metal surface which will initially resist rinsing,
without a drying or fusing operation performed thereon. ` ; ~ `
United States Patent No. ~,585,084 discloses compositions
for coating metal surfaces comprising an organic coating-forming ma-
terial, an oxygen containing oxidizing agent, hydrogen ion and an
anion. Compositions comprising a resin dispersion,
~ , ~
;~3
~ - 1 -
.. . ..
hydrogen ion, fluorlde ion, and an oxidiæing agent selected
from the group co~sisting of hydrogen peroxide and dichromate,
~or coating me-tal surface~ are disclosed in United states
Patent No. 3,592,69~ The coating weight of coatings produced
employing composltions of this kind i5 a function of the time
the surface is contacted with thle composition. These coatings
are capable of being rinsed prior to baking without removin~
all of the polymer or resin deposi~ed on the surface.
Attempts have been made to adjust the rate at which these
compositions form a coating on metal surfaces, by varying the
concentration of hydrogen ion or oxidizing agent therein. It
has been found that varying the concentrations and ratio of
the constituants in these coating compositions in order to
control the film-foxming rate can affect the uniformity and
appearance of the coating as well as the stability of the
working coating bath.
A serious problem that has been encountered in the use
of coating compositions desaribed in the aforementioned ref-
erences is that as the composition is used to coat quantities
of metal surfaces, the composition becomes unstable. This
instability is characterized by flocculation, coagulation or
jelling of the organic coating-forming materials in the compo-
sition. After these compositions become unstable, they can
no longer be used effectively to coat metal surfaces and are
thereby rendered inoperative.
Apparently, these compositions are rendered unstable by
the build-up of large amounts of metal ions which are dissol~ed
from the metallic surface and are then oxidized by the oxidizing
agent in the composition. As metal surfaces are continuously
processed in the~e ~ompositions, the amounts of these metal
ions tend to buil~ up to an undesirable level, thereby result-
ing in coagulation, Elocculation or jelling o the dispersed
resin therein. ~ttempts have been made to prevent the compo-
sition from becoming unstable by either removing the excess
metal ions from the composition or by adding additional dis-
persing agent to the composition.
When these known compositions are contacted with, for
instance ferrous metal surfaces, apparently iron is dissolved
from the surface by the hydrogen ions present in the compo-
sition to form ferrous ions. The oxidi~ing agen~ in the
composition acts on these ferrous ions to form ferric ions.
Due to the action of the oxidizing agent which oxidizes the
already dissolved metal ions to a higher valence state, thereby
causing the metal surfaces to be constantly attacked by the
hydrogen ion present, undesirably high concentrations of ferric
ions are accumulated. In a commercial operation, where large
quantities of metal are processed, these known coating compo-
sitions will require constant replenishment of dispersing agent
or removal of metallic ions since the acid and oxidizi~g agant
therein causes quch high amounts of the ferric ion to enter
the bath, due to the vigorous attack of the metal suxface by
these constituents.
A constant stability problem arises in these compositions,
since there is constant generation of ferric ion, due to the
conversion of ferrous ion, and apparent interaction between
the ferric ion and the dispersing agent which maintains the
resin par~icles in the dispersed state, thereby causiny ro-
agulation and jelling.
, . . .
, ,
It is an object of the present invention to provide an improved
process for forming an organic resinous coating on a metal surface. It
is also an objection of this invention to provide a method and composition
for applying resinous coatings to metal surfaces, the coating rate at which
said coatings are deposited, controlled by the amount of appropriate metal `
present in the coating composition.
It is an object of this inven~ion to provide a process for con~
tinuously depositing an organic coating on quantities of metal surfaces
without the rapid generation of large amounts of metallic ions which affect
the stability of the composition.
A concomitant object of the present invention is to provide
organic coatings on metal surfaces, whose coating weight is a function of
contact time with the coating composition.
It has been discovered that a uniform smooth organic coating
can be formed on a metal surface in a short time by the use of an aqueous
coating composition consisting of a metal compound, acid, and particles of
resin dispersed therein. The coating thickness, or the rate at which a
coating is formed, can be readily controlled by adjusting the amount of
metal added to the aqueous coating composition in the form of a metal com-
pound.
The invention accordingly provides a process for applying a
resinous coating to a metal surface comprising immersing the surface in an
acidic aqueous coating composition comprising about 5 to about 550 g/l of
dispersed solid resin particles, and of pH within the range of about 1.6 to
about 5 and prepared from hydrofluoric acid, and including metal selected
from the group consisting of chromium, cobalt, copper, silver, cadmium, tin,
lead, and ferrous iron, the source of said metal being about 0.025 to about
50 g/l of a metal-containing compound which is soluble in said composition
and contains said metal, said composition being effective in forming on said
metal surface a resinous coating which increases in weight or thickness the
~ - 4 _
. - - .. .. . . . .. . . . . .
~fl3~
longer said surface is immersed in said composition, and withdrawing the
resinous coated surface from said composition.
According to ano~her aspect of the invention, there is provided
a process for applying a resinous coating to a metal surface comprising
immersing the surface in an acidic aqueous coating composition comprising
about 5 to about 550 g/l of dispersed solid resin particles, and of pH
within the range of about 1.6 to about 5 and prepared from hydrofluoric acid,
and about 0.025 to about 50 g/l of a metal-containing compound which is
soluble in said co~position, the cationic species of said compound contain-
ing a metal selected from the group consisting of non-ferric transition ele-
ments and Group IV elements of the Periodic Table, said composition being
effective in forming on said metal surface a resinous coating which increases
in weight or thickness the longer said surface is immersed in said composi-
tion, and withdrawing the resinous coated surface from said composition.
The invention also provides acidic aqueous coating compositions
as defined in these processes.
It should be understood that "aqueous coating composition"
means the aqueous acidic composition having dispersed resin, metal from a
metal containing compound, acid, and suitable additive ingredients as de-
scribed herein, which is employed in the process of this invention.
~ s
.!~ ~ - ~ a -
:~ , . . .
It should be understood that: "metal surfaces" means
various metal surfaces, ~uch as aluminum, zinc, iron,
nickel, tin and lead surfaces and any other surface of metal~
which are selected from a group of metals ranging from
aluminum to copper in the order of the "ionization tendency",
and which are present in the forms of pure metal and its
alloys and also in the forms of plated metal surfaces. The
term "iron surfaces" or "ferrous metal surface~" employed
herein thus encompasses a wide variety of steels, iron, and
iron alloys, including alloys of iron with chromium and/or
nickel. The term "aluminum surfaces" employed herein encom-
passes a wide variet~ of aluminum and aluminum alloys, inclu-
ding heat resistant alloys, corrosion resistant alloys and
high strength aluminum alloys.
The term "zinc surfaces" employed herein encompasses a
wide variety of zinc, zinc alloys and zinc plated metals, in-
cludin~ hot dip galvanized steel and electrogalvanized steel.
The term "copper surfaces" employed harein encompasses a wide
-variety of copper and copper alloys, including brass, bronze
and German silver. The term "lead surfaces" employed herein
encompasses a wide variety of lead and lead alloys, including
soldering metals. The term i'tin surfaces" employed herein
encompasses a wide ~ariety of tin, tin alloys, and tin plated
metals, including tin plate. The term "nickel surfaces" em-
ployed herein encompasses a wide variety of nickel; nickel
alloys and nickel plated metals, including nickel plated steel.
Of course, it is understood that the process of the
present invention i9 carried out in a s~bstantially electro-
static field-free environment, and the use o~ electricity and
equipment and control instruments required to operate an electro-
coat proce~s i9 avoided.
--5--
3;~
The p? icles of resin dispersed in the compo3ition, will
ordinarily b~ in the form of latex of the resin. Latices, dis-
persions o~ insoluble resin par~icles in water, are readily
available and those sold commercially can be utilized herein.
These commercially available la~ices will usually contain other
ingredients such a-~ emulsifiers and protective colloid~. E~-
amples of commerciall~ available latices which can be employed
and which can be regarded as the preferred materials for use
in the aqueou~ coating composltions of this invention axe
Hycar X 407 (manufactured by Japanese Geon Co.j Ltd.)
.~. styrene butadiene copolymer
Goodrite 1800 X 72 (manufactured by Goodrich Chemical Corp.)
... styrene butadiene copolymer
Durex 637 (manufactured by W.R. Grace)
... styren~ butadiene copolymer
Pliolite 491 (manufactured by Goodyear Rubber and
Chemical Corp.)
... styrene butadiene copolymer
Hycar ~X 814 (manufactured by Japane~e Geon Co., Ltd.)
... acrylic copolymer
Boncoat 9404 (manufactured by Dainippon Ink & Chemicals,
Inc.)
... acrylic copolymer
Nipole 1571 (manu~actured by Japanese Geon Co. r Ltd.
... acrylnitrile butadiene copolymer
Synthemal~9404 (manufactured by Nihon Reichold Co. Ltd.)
... ac~ylic copolymer
Polysol~AP 300 ~manufactured by Kobunshi Kagaku Kogyo
Co., ~td.)
... acrylic copolymer
Polysol EVA P 1 (manufactured by Kobunshi Kagaku Koyyo
Co., Ltd.)
... ethylene-vinyl acetate copolymer
Poly-em 40 ~manufactured by Gulf Oil Corp.)
... polyethylene
f f~ 6-
,
~ 4~ ~
Other coating-forminy resin dispersions or emulsions can
be employed herein so long a~ the latex is stable in the
presence of the other ingr~dients in the compositions of the
present invention.
The amount of ~ispersed resi;n employed in the coating
composition will depend on the amount of resin which can be
dispersed therein and the amount needed to provide suffi~ient
resinous material to form a coating. The concentration of dis-
persed resin can vary over a wide range and should prefexably
be from about 5 to about 550 g/l of re~in. It is un~er~tood
that the volume of latex necessary to provide the paxticular
amount of resi~ in the coating composition will depend on the
speai~ic amount of resin solids dispersed in the latex to be
employed.
For the coating process of the present invention to be
efected, the concentration o~ metal in the coating composition
should be maintained by employing a water soluble metal com-
pound or a metal compound soluble in acidic aqueous compositions.
The metal compound can be present in the composition in an
amount from about .025 grams/liter to about 50 grams/liter.
The concentration of metal in the composition will depend on
the particular metal and metal compound employed. For example,
ferric fluoride can be added to the coating composition in an
amount from about 1.0 gram/liter to about 50 grams/liter and
silver fluoride can be added to the bath in an amount from
about 0.1 grams/li~er to about 10 grams/liter. A wide variaty
of metal compounds can be employed in the practice of the
present inve~tion. Selection of the compound to be employed
will depend on its commercial availability and its ability to
liberate metal in the aqueous cohting composition.
7--
:~3~
For example, me~al compounds which will yield ~uffioient
metal in the aqueous acidic coat:ing composition for aluminum
surfaces and zinc surfaces are ferric fluoride, ferrous oxide,
ferric oxide, cupric sulfate and cobaltous nitrate. Metal
compounds which will yield sufficient metal in the aqueous
acidic coating compositions for ferrous,tin, and laad surfaces
are ferric fluoride, ferrous oxids, ferric phosphate and
silver fluoride. Metal compounds which will yield sufficient
metal in the aqueous acidic coating composition for copper
surfaces are silver fluoride and silver acetate.
The acid to be employed in the composition of the present
invention can be an inorganic or an organic acid. Typical
examples of inorganic acids that can be employed are sulfuric,
hyrochloric, hydrofluoric, nitric, and phosphoric acid. Ex-
amples of organic acids that can be employed are acetic~
chloracetic, and trichloracetic acid. The acid to be employed
in the process of the present invention mu~t be present in
sufficient quantity to maintain the pH of the solutian at its
desired level. The p~ of the coating composition should be
maintained at a level within the range of from about 1.6 to
about 5Ø
The ac1d employed in the composition will dissociate to
yield hydrogen ion and an anion. It has been observed that
particularly good resul s are obtained when the acid employed
in the coating composition is hydrofluoric acid. The preferred
method of making the composition acidic comprises the use o
hydrofluoric acid, which permits a simple means for control of
pH in the coating composition and introduces an anion, that is
fluoride ion, which allows for satisfactory operation Gf the
process. The use of hydrofluorlc acid prevents the deliberate
_~_
- ~7~ J~
inclusion of anions which may be undesirable and detrimental
to the coating process. It ~hould ~e understood that hydro-
fluoric acid is a preferred acid ko be employed in the aqueous
coating composition, but that oth~r acids such as those de-
scribed above can be employed with satisfactory results.
A preferred embodiment of this in~ention is to employ an
operating aqueous coating composition comprising a combination
of constituents consisting essentially of an anionic stabilized
resin dispersion (negatively charged disper~ed resin particles)
having about 5 to about 550 grams/liter of resin ~olids, from
about 1 to about 5 grams/liter of erric fluoride trihydrate,
and an acid in an amount 9ufficient to impart a pH to the
aqueous composition of from about 1.6 to aboùt 5Ø
A distinct advantage of the present process is that large
quantities of metal surfaces can be contacted with the aqueous
coating composition, for example, with little build-up of
ferric ion caused by the acid attack on the ferrous metal
surface. The present invention allows for controlled amounts
of ferric ion in the coating composition. It has been found
that the metal loss from a surface contacted with the aqueous
coating composition will not exceed 40 mg per square foot per
minute. The process of the present invention can be contin~
uously effected for longer periods of time o~ greater ~uantities
of metal.
In the coating operation, the metal substrate to be treated
is brought into contact with the aqueous coa~ing compo~ition
under suitable conditions of ~emperature and contact time. The
time of treatment ofthe metal surface with the aqueous coating
composition can be from about 15 seconds to about 10 minute~.
~ _g
i
., ,
3~ J
It will be appreciated that with the use of the aqueous coating
composltion desc~ibed herein, the coating weigh~ of the deposited
coating will increase with longer exposure of the metal ~urface
to the action of the coating composition. Therefore, the coating
time to be employed will depend on the coating wei~ht ~esired.
Preferably, contact time between metal substrate and coatlng
composition should be from about 30 seconds to about 5 minutes.
It should be noted that the coating weight for a particular
coating composition will increase up to a maximum a3 the time
of treatment is increased.
The coating procesR can be operated at temperatures from
about 40F to about 120F. It is preferable to operate the
coating bath at ambient temperature, that is from about 60F
to about 90F. Generally, a slight change in the temperature
of the aqueous coating composition will not necessitate sub-
stantial alteration of treating time and conc2nt~tion para-
meters.
The process of the present invention can be effected by
employing known contacting techniques. Contact can be effected
by either immersion or flowcoating to produce the desired
surface coating. Preferably, the aqueous coating composition
will be contacted with the metal surface by conventional
immer~ion methods.
Subse~uent to contact with the a~ueous coating composition,
the surface should be dried to allow the resin to be fused.
Prior to the drying operation, the coated surface can be ex-
posed to an oxidative environment and then rinsed with water.
It has been found that when the surface is exposed to an
oxidative environment, such as allowing the surface to stand
in air, for a time from about 15 seconds to about lO minutes,
-10-
.
follow~ by water rinsing, and ~hen dried, the surface possesses
a tigh~, adheren~, and uniform coating. It ~hould be understood
that the time of exposure to air or other oxidati~e environment
should not be long enouyh to allow the deposited coating to dry
prior to rinsing. The exposure time to be employed will depend
somewhat on the type of resin ut:ilized to form the coating.
Subsequent to the water rinse, the coated surface can be
rinsed with an aqueous rinse solution containing hexavalent
chromium or hexavalent chromium and reduced forms of chromium.
Subsequent to the rinse treatment, the coated surface should
be dried or baked. This can be accomplished by conventional
techniques, such as passing the metal surface through a heated
environment such as an oven, qubjecting it to a warm air
stream, or by allowing it to dry at ambient temperature. Should
speed be a necessaxy factor, any method of forced drying the
surface can be accomplished. When a heated environment is
used, ~rying may be carried out at tempexatures above 150~F,
and preferably from about 300F to about 500F. It should be
understood that whatever temperature is employed will depend
to some extent on the type of latex or resin dispersion and
the drying time that has been utilized.
The aqueous coatlng compositions of the present invention
described hereinabove are capable of producing coatings on a
metal s~rface which portray excellent adhesion to the surface
and have excellent corrosion resi tant properties. However,
the aqueous coating compositions and the coatings deposited can
be enhanced by incorporation into the coating composition of
added constituents described hereinbelow.
An oxidi~ing agent may be incorporated into the aqueous
coating compo~ition. Any oxidizing agent can be employed and
can be conveniently added to the composition as a water soluble
3t~ ~
compoun~. Typical examples of oxldlzing agents that can be
used are hydrogen peroxide, dichromate, perman~anate, nitrate,
persulfate, and perborate. In some instanceq, ~he addition of
an oxidizing agent to the composition in an amount sufficient
to providq from about .01 to about 0.2 of oxidizing equivalent
per liter of composition may be desirable to obtain a coating
having particular properties, sueh as heavier coating weights.
It has been observed that addition of an oxygen containing
oxidizing agent to the aqueous coating composition can result
in highex coating weights than would ordinarily be obtained
employing the same contact time. Should an oxygen containing
oxidizing agent be employed in the composition, it will be
appreciated that the working coating bath will re~uire regorous
eontrol proeedures, since the composition, when in contact
with the metal workpieces, will generate large amounts or metal
ions. It will be appreciated that addition of an oxidizing
agent to the aqueou~ eoating composition is not deemed dèsirable
when large quantities of metal are to be processed. (The
term "oxidizing equivalent" when used herein means the number
of grams of oxidizing agent used, divided by the equivalent
weight of the oxidizing agent. The equivalent wei~ht of the
oxidizing agent i5 the gram molecular weight of the agent
divided by the changing valence of all stoms in the molecule
whieh ehange valenca, usually one element.)
A eoalescing agent can be incorporated into the aqueous
eoating composition. The addition of a coalescing agent will
further enhance the appearance and the corrosion resistant
qualities of the deposited coating. A typieal example of a
coaleseing agent which can be employed is ethylene glycol
monobutyl ether. The coalescing agent can be present in the
compo.sition in an amoun'c from about S grams/liter to abo~t
30 grams~ er.
-12-
. . . ~ , .
.
The co~ting ~omposition of the present invention may be
formulated so as to incorporate water dispersible pigments known
to the art. Vaxiations in the color of the deposited coating
can be realized by adding pigments such as phthalocyanine blue,
phthalocyanine green carbon black, quinacridone xed, iron
oxide red, iron oxide yellow, lead chromate, and chrom~ oxide
green. These pigments provide excellent color variations with
no sacrifice in coating ~uality or corrosion resistance.
To assure satisfactory wetting of the metallic surface
during treatment with the coating composition, it may be
desirable to inc0~porate into ~he composition a small amount
of a wetting agent or surface active agent. Preferably~ nonionic
or anionic type wetting agents should ~e employed. T~pical
examples of wetting agents which can be utilizèd are alkyl
phenoxy polyethoxy ethanol and sodium salts of alkylaryl
polyether sulfonate.
Should a dry pigment be used in the coating composition,
it can be dispersed in the aqueo~s coating composition by
conventional procedures, such as mixing the pigment with a
small amou~t o nonionic or anionic surface active agent and
water, sald mixture agitated with a high speed mixer, then
adding the pigment - surface active agent mixture to the
already prepared coating composition with further agitation.
A pigment, such as iron oxide red or iron oxide yellow,
which is partially soluble in the aqueous coating composition,
can be employed as a source for metal~ particularly iron.
Should the pigment be employed to ~erve as a source for iron,
a sufficient amount of piyment must be added to pxovide suf-
ficient iron in the composition to effect the process of the
present invention.
-13-
~i3l~3~
To demon~trate th~ present inventicn, a series of examples
are presented showing -the use of particular aqueous coating
compositions. It will be observed that some of the examples
include the use of various other additives which have been
found to be suitable for usP in the compositions. The examples
presented below are illustrative of this invantion and are not
considered as limiting for other ~aterials and operative oon-
ditions falling within the scope of the invention that miyht
be substituted.
In some of the examples below, corrosion tests and adhesion
te~ts were run on the test panels. When salt spray corrosion
tests were run on representative panels, the treated panels
were scribed so that base metal was exposed. Panels were
subjected to 5~ salt spray and were rated inaccordance with
ASTM~-1654-61, by mea~uring tha average failure of the paint
film rom the scribe.
Adhesion tests were run on panels, using impact and
cross-hatch test prQcedures which are commonly employed in the
testing of paints. In the impact test, the test surface is
impacted by a falling 1/~" ball with a force measured as
50 kilogram centimeters, thereby deforming the test surface.
Subsequent to impact, the deformed surface is inspected ~or
loose or cracked paint, usually on the reverse side of the
impact, and rated in inches of paint failure. In the cross-
hatch test, the surface is scrib~d with parallel lines, ap-
proximately 1 millimeter apart and out through to bare metal.
Duplicate lines are scribed at right angles to make a cross-
hatch pattern. Scotch brand cellophane tape is pressed smoothly
over the scribed area. After several seconds, the tape is
pulled back rapldly so that the tape is turned back upon itself
approximately 180 from i~s original pressed position Results
are reported in the degree of failure noted, that is none,
slight, moderata, or heavy loss of coating.
EXAMPLE 1 - 7
Panel~ of each metal described in Table 1, cleaned in a
conven~ional alkali metal silicate cl~eaning solution, were
immersed for 3 minutes in an a~ueous coating composition
comprising the following conRtituents:
Grams
Styrene-butadiene re~in (HYCA ~ ~X 407) 180
Hydrofluoric acid 3
Ferric fluoride (trihydrate) 5
Water to make 1 liter
Hycar LX 407 was employed as tha source for the styrene-
butadiene re~in, (manufactured by Japanese Geon Co., Ltd., and
containing 48% resin solids). The aqueous composition was
prepared by mixing the resin with water, and adding hydrofluoric
acid, and ferric fluoride with continuous agitation.
The test pa~els were removed from the coating bath and
dried in an oven at 356F for 10 minutes. The average coa~ing ~ -
weight for the panels were as shown in Table 1, and the coatings
produced were obser~ed to be smooth and uniform.
,. '
Table 1
¦ E~LE ~) r Metal Surface Coat ng Weigh~
' ~1' . ~.
1 dull steel 1673 ~18)
~ 2 r r
2 aluminum 1951 (21)
_ .... .. ....
3 hi~h strength Al alloy 213~ (23)
. ..................... f4 - . ~
4 zillc 1673 tl8)
. . . _ ~-
1 5 h~t ~ip g~llv~nized stcel 1766 (19)
--~ . .~ .. _.___
- 6 tin ylute 1394 (15)
. ':
l 1301 (14~
... . . . .....
-15-
:. ::
. ., . - , -
\
~1. JIS G-31~1, SPC-C
*2. JIS H-4000, ~-1050P
*3. JIS H-4000, A-2024P
*4. JIS H-4321, First Clas~; ;
*5. JIS G-3302, SPG-2C
*6. JIS G-3303, SPT-E
*7. JIS H-4301, PbP
EXAMPLE 8 - 58
.. , .. __ '
These Examples were run to illustrate the use of various
metal compounds as the source for metal ion in the aqueous
coating composition.
The constituents in the respective compositions are re-
ported below in Table 2, along with the measured average weight
of the coatings produced.
The aqueous compositions employed in Examples 8 - 58 were
prepared as set forth in ~Xample 1 - 7, except that different
~ources for metal were employed in each case.
Panels of each metal described in Table 2 were cleaned in
a conventional alkali metal silicate cleaning solution, then
immersed in the respective coating composition set forth in
Table 2 for 3 minutes. The pH of each aqueous coating composi-
tion employed herein was between 1.6 and SØ The panels were
dried in an oven at ~56F for 10 minutes.
The average weight of the coating on the test panels was
measured and is noted in Table 2.
-16-
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EXAMPL~ 59 - 72
These Examples were run to illustrate the use of various
acids as the source for acid in the aqueous coating composition.
~he constituent~ in the respective coating compo itions are
reported below in Table 3, along with the measured average
w ight of the coatings produced.
The aqueous coating composltion employed in Example 59 -
72 were prepared as set forth in Example 1 7, except that
different sources for acid were employed in each case.
Panels o~ each metal described in Table 3 were cleaned
in a conventional alkali metal silicate cleaning solution, then
immersed in the respective coating composition set forth
in Table 3 for 3 minutes. The pH of each a~ueous coating
composition employed herein waq between 1.6 and 5Ø
The panels were then dried ln an oven at 356CF or 10
minutes. The average weight of the coating on the test panels
was measured and is noted in Table 3.
-23-
~r
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EXAMPL.E 7 3 - 8 3
These ExAmples were run to illustrate the use of various
resins as the ~ource for resin in the aqueous coating composition.
The constituents in the respective coating compositions are
reported below in Table 4, along with the measured average
weight of the coatings produced.
The aqueous coating compositions employed in Example 73 -
83 wexe prepared as set forth in Example 1 - 7, except that
different sources for resin wPre employed in each case~
Panels o each metal described in Table 4 were cleaned
in a conventional alkali metal silicate solution, then immer~ed
in the respective coating composition set forth in Table 4 for
3 minutes. The pH of each aqueous coating compo~ition employed
herein was between 1.6 and 5Ø
The panels were then dried in an oven at 356F for 10
minutes. The average weight of the coating on the test panels
was measur~d and is noted in Table 4.
~_
.
It~ ~
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~ ~ ~ ~ ~ N
~ O ~ O ~ CX~ O ~O O ~0 ~' 0
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:
_ . _ _ .. .
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EXAMPLE 84 - 89
; Panels of each metal described in Table S were immersed
in the aqueous coating composition comprising the following
~on~tituents:
~e~ Grams
A Styrene-butadiene resin ~HYCAR~ X 407) 200.0
Hydrofluoric acid . - 2.5
Hydrogenperoxide 1.5
Ferric fluoride (trihydrate) 3,0
~ water to make 1 liter
: .
The test panels were contacted with the coating composition -.
for a period of 3 minutes, then dried in an oven at 320F for
15 minutes. The average weight of the coatings is also listed
~ in ~sble 5. It has be~n also observed in further experiments
:~ that the average weight of the coatings decreased by about 3 - .
10 ~rams/m2 when each metal panel described in Table 5 were .
, ~mmersed ln the aqueous coating composition comprising the .`
.~ above-mentioned constituents but hydrogenperoxide.
~ . . .
.
`! Table 5
~ ~ Metal panel used as a Coat mg weight : :
. Nb. substrate (g/~2) mg/ft2 ~
.` . . .~ . . . _ . __~
. 8~ Dull steel (31~ ~ 2881 :~
. B5 Aluminun (1~3 1673 ~: :
.,, , . ........ . .. ___ _
~.. , ~86 2i~c : t~6) 2416 ~ :
.. ~, ._ _ _ ~ _ . ~,
~ . 87 T m plate (15~ 1394
.i ~
.~ 88 Lead tl2) 1115
.. _ . _ . _ _ _
89 Copper (13~ 1208
-28-
.. . .
. ~ . . . . . . . . . . ... .. ... ..... . ~ .
: . ,
:: .
3~
EXAMPLE 90 - 94
.
Panels of each metal described in Table 6 were immersed
in the aqueous coating composil:ion comprising the following
constituents. The test panel~ were contacted with the coating
compo~ition fox a period of 2 minutes, then dried in an oven
at 392F for S minutes. The average weight of the coatings
produced is also listed in Tab].e 6.
It should be noted that the aqueous coating composition
employed herein contained chromic acid as an oxygen containing
oxidizin~ agent, and butylcellosolve as a coalescing agent.
Component Grams
Styrene butadiene re~in (HYCAR LX 407) 160
Hydrofluoric acid 3
Chromic acid anhydride
Ferric phosphate (tetrahydrate) 8
Butylcellosolve 10
Water to make 1 liter
Table 6
. . _ ... _ ..... _ _ . _ _ ~
E~L~ Metal gurface Co;t ~ wci
90 ~lll steel ~21) lg52
, ..... _._
91 ~igh s~rength A1 alloy (Z7) 2509
.... . ... ... _ ~
92 f~t dip galvanized steel (23) 2138
~ , . " . .. ~. . . __
93 Tin plate (1~ lil5
_, . ~ . . _
Brass (15) 139~
~ .
~29-
-
~.~ i L'7/~ 4)~
EXAMPLE 9S - 101
various metal panels noted in Table 7 were employed in
this procedure. The test panels were cleaned in a conventional
alkali metal ~ilicate cleaning solution and then immersed in
the aqueous coating composition described below. ~he panels
. were then baked in an oven at :392F for 5 minutes. The average i.!
` coating weight of the coatings produced waq measured and is ~
listed in Table 7.
Component Grams
Styrene butadiene resin (HYCA ~ LX 407) 180
' Lead chromate pigment 95
.~ ~
Anionic surface active agent ~Demol-P) 5
Ferric fluoride ~trihydrate) 8
~: Hydrofluoric acid 3
:~- Water to make 1 liter
.: It will be observed that lead chromate piyment was employed
in the composition. The lead chromate, an anionic surfactant
~Demol-P) and water were mixed together and milled for 16 hours
' prior to addition to the already prepared composition containing
:~, the styrene butadiene resin, hydrofluoric acid and water.
....
~ The lead chromate pigment employed in the composition
-~ was Kiku-Jirushl G ~manufactured by Kikuchi Kogyo).
t
.i
. 1
'~
.'
e -30
. -, .
':!
Table 7
._ _ ___ ___
- ~. Metal panol us~d a-~ a Coating weight
Ab. substrate ~g~m~) mg/~t2
~.: __ ~ , .~
Dull steel (120) 11152
... ~ . ~ .. .. ~
96 Aluminl~ (4s) 4182
~7 aluminum alloy ~44) 4089
~ . __ .. ... ~ . _
: 98 2inc (66) 6134
__ _. _ ... .. ,_ ...
~ 99 Hot ~ip galvanized steel (89~ 8271 .
. :- . , ~ . . ,~ , .~
100 Tin plate (110) 10~23 .
, . . .. . _ __ .. ~.,
101 Lead ~32) 2974
_ _
-
, EXAMPL-E 102 - 107
Panels o each metal described in Table 8 was immer~ed
' in the aqueous coating compo~ition comprising the following
:` constituents:
Grams
~ Styrene-~utadiene resin (HYCAR LX 407) 200
.~:: Lead chromate pigment (KIXU-JIRUSHI SG-3KB,
manufactured by Kikuchi Kogyo) 50
.~; Ferric oxide pigment (L~APICO~YELhOW LL.XL0,
manufactured by Titan Industry) 30
Anionic Jurface active agent (EMA~ 10,
manu~actured by Kao-Atlas) 3
. - Bydrofluoric acid 3.5
Tap water to make 1 liter
, .
The test panels w~re contacted with the coating composition
- for a period of 3 minutes, then dried i.n an oven Rt 356F for
.. 10 minutes. The average coating weight for the panels were
-31-
.,
:
.,;, . .. .
~ l~3~
shown in Table a, and the coatings produced were observed
. to be smooth and uniform.
. Table 8
,
__ . .~
: No Metal Surface C(o/t2)g w~/8ht
., . . .~ _ .~ .
. 102 Dull steel 75 6970
:~ 103 Aluminum 57 5297
. 104 Zinc 72 6~91
105 Nickel plated steel 10 929
106 Tin plate 76 7063
107 Lead 37 3439
.~.
..,
.. ' ~.
~;~ EXAMP~E 108 - 130
s Various metal panels were cleaned in a conventional alkali
.~ metal silicate cleaning solution and then immersed in the
aqueous coating composition described in Table 9 for 3 minutes.
The panels were then baked in an oven at 392F for S minutes.
.~ ., .
The average ¢aating weight of the coatings produced was
measured and is listed in Table 9.
s~
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r, ) .
EXAMPLE 131
Steel panels were employed in this procedure. The test
panels were cleaned in a conventional alkali metal silicate
cleaning solution and then immersed in the aqueous coating
composition described below for different contact times.
The test panels were then allowed to stand i~ air for 3 minutes
and th~n xinsed with water. The panels were then baked in an
oven at 356F for 10 minutes. The average coating weight of
the coatings produced was measured and i5 listed in Table 10.
Component Grams
Styrene butadiene resin (HYrAR LX 407) 180
' Lead chromate pigment 50
Iron oxide red pigment 50
Anionic surface active agent (Demo ~ P) 5
Hydrofluoric acid 3.5
Water to make 1 liter
It will be observed that lead chromate pigment and iron
oxide red pigment were employed in the composition. The lead
chromate, iron oxide red, an anionic surfactant (Demol-P~ and
water were mixed together ànd milled for 16 hours prior to
addition to the already prepared composition containing the
-~ styrene butadiene resln, hydrofluoric acid and water. The
pH of the aqueous coating composition was measured at 2~8O
, The lead chromate pigment employed in the composition was
-s' Xiku-Jirushi~SG (manufàctured by Kikuchi Kogyo) and iron oxide
~( red pi~ment was Tenyo Bengara 501 ~manufactured by Tone Sangyo).
:;' -
,
-36-
.'''., . . ''
.
i~ ~
, ' . .
T le 10
Coating Weight
Time of I~nerslon _mg/ft2
15 sec. 649
30 sec. 803
1 min. 1224
2 min. 2257
3 min. . 3544
5 min. 5608
- .
As can be seen from Table 10, the coatings deposited on
test ~anels treated in accordance with the present invention
have the property of increased coating weight with increa~ed
; contact time.
.',. ~ - . '.
- EXAMPLE 132
. , : . . :
Steel panels were employed in this procedure. The test
panels were cleaned in a conventaonal alkali metal silicate
cleanin~ solution and the immersed in the aqueous coating
composition described below for 3 minutes. The coated test
.~ . . ~ .
panels were then exposed to the air for periods of time as
noted below and then were rinsed with water. The panels were
- then ~aked in an oven at 356~F for 10 minutes. ;;~ ~ ;
Component Grams
Styrene butadiene resin (HYCAR LX 407) 180
Léad chromate (Xaku Jirushi~5G) 50
Iron oxade (Tenyo ~engara 501) 50
- Anionic surface active agent ~Demol-P) 5
i Hydrofluoric acid ~ 3
/ Wa~er to ma~e 1 liter
~ . :
!
?~ 37-
;
.
,
:
3~
It will be observed that lead chromate pigment and. iron
oxide red plgment wer~ employed in the composition. The lead
chromate, iron oxide, and anionic surf~ctant (Demol-P) and water
were mixed together and milled for 16 hours prior to addition
to the already prepared composition containing the styrene
butadiene resin, hydrofluoric acid and water. The coatings
produced were observed to be smooth and uniform. ~he average
film thickness was measured and is listed in Table 11. The
test panels were subjected to 168 hours salt spray corrosion
~ests and the results are listed in Table 11.
.
Table 11
Film thickness Scribe failure
(microns) ~in inches)
.5 sec. 13 1~32
15 sec. 17 1~32
30 sec. 22 1/32
1 min. ~ 25 1~32
2 min. 28 1~32
3 min. 28 3~32
Impact test~, c~oss-hatch tests, and salt spray corro~ion
te~t were run on representative panels treated in accordance
with some of the aforementioned procedures, that is, Example 1,
2, 4, 6 and Sl. The results of these tests are listed in .-
Tablo 12 and also in Table 13. '
Table 12
I:ilm Ap~e.lrance
Co~ting coatin~ height Imp~ct Test Cross Hatch ~tal
C~osition il~ !gr~m2~ ft2 Result~ Test Result~ Surface
Ex. N~. 1 t~o~ 1673 No f.ailure None null st~el
Ex. Nb. 2 ~-ellelll No f~ilure None Al~inwn
~l) 1952
Ex. ~. 4 ~ d ~l8) 1673 No failur~ None Z~c
~. N~. t~ E~cellent ,~o f~ilure None Tin plat~
(15) l3'34
. N~. Sl ~o~d (l7) tS~O ~o f~ilule None (`~prer
-38-
. Table 13
Film Appe~rancc
L`o~tin~ ~ coatillg~ei~ht Salt spray Met:-l
_npositi~ (gr/m2) m~/ft2 test results ~ surface
. ~o. 102 ~xcellent (75) ~970 No fail~re Dull steel
Ex. No. 103 Caod (57) 5291 Nb failure Aluminum
. Ex. Na. 104 F~cellent (72) 6691 Slight white-rust Zinc
Ex. No. 106 Excellent (76) 7063 No failure Tin plate
o. 12~ ~ood (20) 1859 No failure Copper
(~ Exposure time : lS0 hours3
As can be seen from Table 12 and 13, test panels treated
in accordance with the present invention give acceptable a~hesion
and corrosion test results.
. ~ ~
. . . .
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